This disclosure relates to a cutting tool comprising a holder and a cutting insert arranged exchangeably in the holder.
Cutting tools of this type are employed mostly in metalworking applications, in particular in milling or turning applications. Cutting tools according to the present disclosure are used in particular for plunge-cut turning or longitudinal turning.
In order to ensure optimal metal cutting characteristics, an insert seat which is stable from a mechanical viewpoint, i.e. a mechanically stable receptacle of the cutting insert within the tool holder, is of immense importance. To this end, the cutting inserts which are used are mostly held clamped or wedged in a cutting insert receptacle provided in the tool holder, between an upper clamping finger and a lower clamping jaw. A further important aspect which it is important to ensure is a simple and rapid exchangeability of the cutting insert, since this must be frequently exchanged due to wear.
For the type of clamping of the cutting insert in the tool holder, a multiplicity of widely differing solutions already exists in the prior art.
From DE 10 2006 059 717 A1, a tool in which the cutting insert is clamped in a cutting insert receptacle with the aid of a clamping screw is known, for instance. To this end, in the upper clamping finger is provided a separating slot, which enables the upper clamping finger, when the clamping screw is screwed in, to be at least partially deformed to allow this upper clamping finger to be pressed from above onto the cutting insert.
EP 0 095 062 B1 shows a tool in which the cutting insert is clamped between the upper clamping finger and the lower clamping jaw without the aid of an additional clamping screw. The type of clamping which is shown therein makes use of the principle of self-locking, wherein the upper clamping finger, due to its pretensioning, presses from above onto the cutting insert in a manner similar to a spring. Although no extra clamping screw is required for the clamping, such a tool is disadvantageous, however, in various respects. On the one hand, the self-locking clamping, in the presence of relatively high machining forces, comes up against its limits. On the other hand, a type of clamping slot has likewise to be provided in the tool holder in order to ensure the resilient or self-locking property of the upper clamping finger. Depending on the geometry, such clamping slots can be thoroughly complex in terms of production. Furthermore, nor can the exchangeability of the cutting insert be readily easily ensured. For the exchanging of the cutting insert, a special tool key must namely be used, by means of which the upper clamping finger is expanded in order to release the cutting insert from the tool holder.
A further fastening variant of a cutting insert in the tool holder is known from DE 10 2012 111 240 A1. This document shows a tool comprising a substantially arc-shaped cutting insert, which is clamped in an arc-shaped cutting insert receptacle. The arc-shaped shank of the cutting insert and the arc-shaped cutting insert receptacle are here configured such that the cutting insert, when pushed or rotated into the cutting insert receptacle, is with increasing rotation clamped firmly in the tool holder. Although this type of clamping enables a relatively stable insert seat, such a cutting insert or such a cutting insert receptacle, due to the arc-shaped geometry, is relatively complex in production engineering terms.
In particular for the field of heavy-duty metal cutting, there is therefore demand for alternative types of clamping of a cutting insert on the tool holder, wherein the clamping should enable an extremely stable insert seat. The term heavy-duty metal cutting can be used if workpieces with large and varying machining allowances, machining depths over 25 mm and/or machining widths greater then <8 mm are cut. By heavy-duty metal cutting is also understood the machining of materials which are difficult to cut, such as titanium or nickel-based alloys.